1. Field of the Invention
The present invention is directed to a throughput control system for an agricultural combine wherein the upward force on the forward drum of the feederhouse is measured and is used to control the harvesting speed of the combine.
2. Description of the Prior Art
Agricultural combines are large machines that harvest, thresh, separate and clean an agricultural crop. The resulting clean grain is stored in a grain tank located on the combine. The clean grain can then be transported from the grain tank to a truck, grain cart or other receiving bin by an unloading auger.
A harvesting assembly located at the front of the combine harvests the crop. The harvested crop is directed to a feederhouse for delivering the harvested crop material to a threshing assembly. The threshing assembly may either be a conventional transverse threshing cylinder and concave, or a rotary threshing assembly. The rotary threshing assembly may be arranged axially or transversely. The forward harvesting speed of the combine controls the amount of harvested crop material ingested by the threshing assembly.
The feederhouse comprises a housing that is pivotally mounted to the front of the combine and from which the harvesting assembly is mounted. The interior of the feederhouse is provided with a conveyor for conveying the harvested crop material upwardly and rearwardly into the combine. Typically the conveyor is a chain conveyor having transversely extending slats located between the drive chains. A rear mounted drive sprocket drives the drive chains. The chains pass around a front mounted drum, which floats on top of the harvested crop material. When the front drum has floated to its maximum upward position the harvested crop material exerts an upward force on the front drum.
Various throughput control systems have been proposed to facilitate combine efficiency. Some of these systems sense grain loss using grain loss monitors. Other systems sense crop material throughput and try to maintain a relatively constant throughput of crop material. The earlier the throughput of crop material the better the control system can function. In one proposed method, sensors on the harvesting platform are used to signal throughput before the crop is harvested, see U.S. Pat. No. 4,228,636.